U.S. patent number 9,507,066 [Application Number 14/320,382] was granted by the patent office on 2016-11-29 for eyepiece for near eye display system.
This patent grant is currently assigned to MICROSOFT TECHNOLOGY LICENSING, LLC. The grantee listed for this patent is MICROSOFT TECHNOLOGY LICENSING, LLC. Invention is credited to Douglas C. Burger, Joel S. Kollin, Jaron Lanier.
United States Patent |
9,507,066 |
Kollin , et al. |
November 29, 2016 |
Eyepiece for near eye display system
Abstract
An optical display system configured to transmit light along a
light path to a user's eye, the display system comprising a
circular polarizing reflector configured to reflect light with a
first polarization from an image source, a quarter wave plate
downstream of the circular polarizing reflector in the light path
and configured to rotate the polarization of the light to a second
polarization, and a curved linear polarizing reflector downstream
of the quarter wave plate and configured to reflect the light back
through the quarter wave plate along the light path in the
direction of the circular polarizing reflector. The quarter wave
plate further configured to rotate the polarization of the light
received from the curved linear polarizing reflector to a third
polarization and the circular polarizing reflector further
configured to receive said light from the quarter wave plate and
transmit the light toward the user's eye.
Inventors: |
Kollin; Joel S. (Seattle,
WA), Lanier; Jaron (Sausalito, CA), Burger; Douglas
C. (Bellevue, WA) |
Applicant: |
Name |
City |
State |
Country |
Type |
MICROSOFT TECHNOLOGY LICENSING, LLC |
Redmond |
WA |
US |
|
|
Assignee: |
MICROSOFT TECHNOLOGY LICENSING,
LLC (Redmond, WA)
|
Family
ID: |
53525296 |
Appl.
No.: |
14/320,382 |
Filed: |
June 30, 2014 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
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US 20150378074 A1 |
Dec 31, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B
5/3058 (20130101); G02B 5/3016 (20130101); G02B
27/0172 (20130101) |
Current International
Class: |
G02F
1/1335 (20060101); G02B 27/01 (20060101); G02B
5/30 (20060101) |
References Cited
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|
Primary Examiner: Rude; Timothy L
Attorney, Agent or Firm: Goldsmith; Micah Yee; Judy Minhas;
Micky
Claims
The invention claimed is:
1. An optical display system configured to transmit light along a
light path to a user's eye, the display system comprising: a
circular polarizing reflector configured to reflect light with a
first polarization originating from an image source; a quarter wave
plate positioned downstream of the circular polarizing reflector in
the light path, the quarter wave plate configured to rotate the
polarization of the light from the first polarization to a second
polarization; and a curved linear polarizing reflector positioned
downstream of the quarter wave plate, the curved linear polarizing
reflector configured to reflect the light with the second
polarization back through the quarter wave plate along the light
path in the direction of the circular polarizing reflector; wherein
the quarter wave plate is further configured to rotate the
polarization of the light received from the curved linear
polarizing reflector from the second polarization to a third
polarization; and wherein the circular polarizing reflector is
further configured to receive the light having the third
polarization from the quarter wave plate and to transmit the light
with the third polarization toward the user's eye.
2. The display system of claim 1, wherein the quarter wave plate is
a switchable quarter wave plate configured to rotate the
polarization of the light if the switchable quarter wave plate is
activated and to not rotate the polarization of the light if the
quarter wave plate is deactivated.
3. The display system of claim 1, further comprising: an initial
polarizer positioned upstream of the circular polarizing reflector
on the light path, the initial polarizer configured to receive
light from the image source and transmit light with an initial
polarization along the light path toward the curved linear
polarizing reflector; wherein the curved linear polarizing
reflector is further configured to receive the light with the
initial polarization from the initial polarizer and transmit the
light along the light path toward the quarter wave plate; and
wherein the quarter wave plate is further configured to rotate the
polarization of the light received from the curved linear
polarizing reflector from the initial polarization to the first
polarization and transmit the light along the light path toward the
circular polarizing reflector.
4. The display system of claim 1, further comprising: a fixed wave
plate positioned upstream of the circular polarizing reflector on
the light path, the fixed wave plate configured to receive the
light from the image source and transmit light with the first
polarization along the light path in a direction of a prism
disposed between the fixed wave plate and the circular polarizing
reflector; wherein the prism is configured to receive the light
through a light input side of the prism and reflect the light off
an internal surface of the prism via total internal reflection
along the light path toward the circular polarizing reflector.
5. The display system of claim 4, wherein the image source is
positioned at an angle less than ninety degrees with respect to an
optical axis of the curved linear polarizing reflector so as to
project side-addressed light toward the curved linear polarizing
reflector.
6. The display system of claim 1, wherein the curved linear
polarizing reflector is a curved wire grid polarizing
beamsplitter.
7. The display system of claim 1, wherein the circular polarizing
reflector is a cholesteric liquid crystal reflective polarizer.
8. The display system of claim 1, wherein the circular polarizing
reflector is configured to have a flat shape.
9. The display system of claim 1, wherein the circular polarizing
reflector is configured to have a curved shape.
10. The display system of claim 1, wherein the image source, curved
linear polarizing reflector, quarter wave plate, and circular
polarizing reflector of the display system are mounted in a
near-eye display device.
11. The display system of claim 10, wherein the near eye display
device is incorporated into a housing of a head mounted display
device.
12. A method of transmitting light along a light path to a user's
eye, comprising: reflecting light originating from an image source
having a first polarization off of a circular polarizing reflector
along the light path toward a quarter wave plate; rotating the
polarization of the light from the first polarization to a second
polarization with the quarter wave plate and transmitting the light
with the second polarization along the light path toward a curved
linear polarizing reflector; reflecting the light off of the curved
linear polarizing reflector and transmitting the light along the
light path back toward the quarter wave plate; rotating the
polarization of the light from a second polarization to a third
polarization with the quarter wave plate and transmitting the light
along the light path toward the circular polarizing reflector; and
transmitting the light through the circular polarizing reflector
along the light path toward the user's eye.
13. The method of claim 12, further comprising: rotating the
polarization of the light with the quarter wave plate when the
quarter wave plate is in an activated state and not rotating the
polarization of the light when the quarter wave plate is in a
deactivated state.
14. The method of claim 12, further comprising: converting the
polarization of the light originating from the image source to an
initial polarization via an initial polarizer positioned upstream
on the light path from the circular polarizing reflector;
transmitting the light from the initial polarizer along the light
path toward the curved linear polarizing reflector transmitting the
light through the curved linear polarizing reflector along the
light path toward the quarter wave plate; rotating the polarization
of the light from the initial polarization to a first polarization
with the quarter wave plate; and transmitting the light from the
quarter wave plate along the light path toward the circular
polarizing reflector.
15. The method of claim 12, further comprising: converting the
polarization of the light from the image source to a first
polarization via a fixed wave plate positioned upstream of the
circular polarizing reflector on the light path; transmitting the
light from the fixed wave plate along the light path toward a prism
positioned on the light path between fixed wave plate and the
circular polarizing reflector; reflecting the light via total
internal reflection off of an interior surface of the prism; and
transmitting the light along the light path toward the circular
polarizing reflector.
16. The method of claim 15, further comprising: transmitting the
light from the image source at an angle less than ninety degrees
with respect to an optical axis of the curved polarizing
reflector.
17. The method of claim 12, wherein the curved linear polarizing
reflector is a curved wire grid polarizing beamsplitter.
18. The method of claim 12, wherein the circular polarizing
reflector is a cholesteric liquid crystal reflective polarizer.
19. The display system of claim 12, wherein the circular polarizing
reflector is one of a flat or curved shape.
20. A method of transmitting light along a light path to a user's
eye, comprising: converting the polarization of light from an image
source to a first polarization via a fixed wave plate positioned
upstream of a circular polarizing reflector on the light path;
transmitting the light from the fixed wave plate along the light
path toward a prism positioned on the light path between fixed wave
plate and the circular polarizing reflector; reflecting the light
via total internal reflection off of an interior surface of the
prism; transmitting the light along the light path toward the
circular polarizing reflector; reflecting the light originating
from the image source having the first polarization off of a
circular polarizing reflector along the light path toward a quarter
wave plate; rotating the polarization of the light from the first
polarization to a second polarization with the quarter wave plate
and transmitting the light with the second polarization along the
light path toward a curved linear polarizing reflector; reflecting
the light off of the curved linear polarizing reflector and
transmitting the light along the light path back toward the quarter
wave plate; rotating the polarization of the light from a second
polarization to a third polarization with the quarter wave plate
and transmitting the light along the light path toward the circular
polarizing reflector; and transmitting the light through the
circular polarizing reflector along the light path toward the
user's eye.
Description
BACKGROUND
Mixed reality devices allow users to view the real world while
simultaneously viewing computer generated graphics overlaying real
world objects and scenery in the user's field of vision. These
graphics may be used by the device to enhance the user's viewing
experience in many ways, such as by displaying information about
objects or locations viewed by the user.
Common designs for mixed reality devices utilize reflective
beamsplitters and mirrors to direct both ambient light from the
real world and light from an electronic display device toward a
user's eye. In a typical design, ambient light enters the device
through one beamsplitter while light from an electronic display
enters through a second beamsplitter. Light from each source
travels along separate light paths before being overlaid and
directed out of the system toward the user's eye. In order to
properly direct the light, however, the light paths within the
system often require the light to pass through or reflect from the
first or second beamsplitter one or more times.
Reflective beamsplitters are typically designed to transmit or
reflect only a portion of incident light. Thus, mixed reality
devices are severely limited by the amount of light intensity lost
each time the light in the system reflects from or is transmitted
through one of the beamsplitters. As a result, the brightness of
the light in the system is diminished and the contrast between the
ambient light entering the system and the light generated from the
electronic display device cannot be properly controlled. Such an
effect reduces the sharpness of graphics displayed on the device
and negatively impacts the user's viewing experience. In addition,
the loss of light from the electronic display requires the device
to expend more power to produce visible graphics and thus reduces
the overall battery life of the device.
SUMMARY
An optical display system configured to transmit light along a
light path to a user's eye is provided. The display system may
comprise a circular polarizing reflector configured to reflect
light with a first polarization from an image source, a quarter
wave plate downstream of the circular polarizing reflector in the
light path and configured to rotate the polarization of the light
to a second polarization, and a curved linear polarizing reflector
downstream of the quarter wave plate and configured to reflect the
light back through the quarter wave plate along the light path in
the direction of the circular polarizing reflector. The quarter
wave plate may be further configured to rotate the polarization of
the light received from the curved linear polarizing reflector to a
third polarization and the circular polarizing reflector may be
further configured to receive said light from the quarter wave
plate and transmit the light toward the user's eye.
This Summary is provided to introduce a selection of concepts in a
simplified form that are further described below in the Detailed
Description. This Summary is not intended to identify key features
or essential features of the claimed subject matter, nor is it
intended to be used to limit the scope of the claimed subject
matter. Furthermore, the claimed subject matter is not limited to
implementations that solve any or all disadvantages noted in any
part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A shows an optical display system to direct light from an
image source to a user's eye in accordance with an embodiment of
this disclosure.
FIG. 1B shows the system of FIG. 1A further configured to prevent
an unmagnified image from reaching a user's eye by deactivating a
quarter wave plate.
FIG. 1C shows the system of FIG. 1A further configured to control
the transmission of light to the user's eye by activating and
deactivating a quarter wave plate at a set frequency.
FIG. 2 shows the system of FIG. 1A further configured to include a
prism positioned in the light path between the image source and the
user's eye, the prism configured to reflect light from the image
source via total internal reflection or other means.
FIG. 3A shows an embodiment of the system of FIG. 1A mounted in a
near-eye display system and incorporated into the housing of a
head-mounted display device.
FIG. 3B shows a view of the head-mounted display device of FIG. 3A
from a user's perspective.
FIG. 4 shows a flowchart depicting a method of transmitting light
along a light path to a user's eye in accordance with an embodiment
of this disclosure.
FIG. 5A shows a step of the flowchart of FIG. 4 expanded to include
steps relating to an embodiment of the present disclosure.
FIG. 5B shows a step of the flowchart of FIG. 4 expanded to include
steps relating to an embodiment of the present disclosure.
FIG. 6 shows a simplified schematic illustration of an embodiment
of a computing device in accordance with an embodiment of this
disclosure.
DETAILED DESCRIPTION
As described above, current designs for mixed reality display
devices suffer from limitations due to the inefficiency of
reflecting light multiples times from traditional beamsplitters. To
address these issues, embodiments are disclosed herein that relate
to an optical display device which may combine the advantages of
highly efficient circular and linear polarizing reflectors with the
use of a switchable wave plate to produce a mixed reality device
with improved efficiency.
FIG. 1A depicts an optical display system 10 that may be configured
to transmit light along a light path 12 to a user's eye 26. The
display system 10 may comprise a circular polarizing reflector 20
configured to reflect light with a first polarization P1
originating from an image source 14 as well as a quarter wave plate
18 positioned downstream of the circular polarizing reflector 20 in
the light path 12. The quarter wave plate 18 may be configured to
rotate the polarization of the light from the first polarization P1
to a second polarization P2. A curved linear polarizing reflector
16 may be positioned downstream of the quarter wave plate 18 and
may be configured to reflect the light with the second polarization
P2 back through the quarter wave plate 18 along the light path 12
in the direction of the circular polarizing reflector 20. The
quarter wave plate 18 may be further configured to rotate the
polarization of the light received from the curved linear
polarizing reflector 16 from the second polarization P2 to a third
polarization P3. The circular polarizing reflector may be further
configured to receive the light having the third polarization P3
from the quarter wave plate 18 and to transmit the light with the
third polarization P3 toward the user's eye 26.
The circular polarizing reflector 20 in optical display system 10
may be configured to transmit one of either right-hand polarized or
left-hand polarized light and to reflect the other. Likewise, the
curved linear polarizing reflector 16 may be configured to transmit
one of S-polarized or P-polarized light and reflect the other. The
quarter wave plate 18 may be configured to rotate the polarization
of the light in a four-phase pattern alternating between linear and
circular polarization. For example, the quarter wave plate 18 may
be configured to rotate S-polarized light to right-hand circular
polarized light after a first pass, rotate the right-hand circular
polarized light to linear P-polarized light after a second pass,
and rotate the P-polarized light back to left-hand circular
polarized light after a third pass.
In FIG. 1A, light of polarization P1 may reflect from circular
polarizing reflector 20. In certain embodiments, polarization P1
may be one of right-hand circular polarization or left-hand
circular polarization. The light of polarization P1 traveling along
light path 12 may next pass through quarter wave plate 18 and
obtain the polarization P2. In certain embodiments, P2 may be one
of linear S-polarization or P-polarization. The system 10 may next
be configured such that light of polarization P2 next reflects off
of the linear polarizing reflector 16 and passes through the
quarter wave plate 18 a second time, obtaining a polarization P3.
In certain embodiments, the third polarization P3 will be the
opposite circular polarization of the polarization P1. The system
10 may then be configured such that light of polarization P3 passes
through the circular polarizing reflector 20 along the light path
12 toward the user's eye 26.
The display system 10 may be further configured such that the
quarter wave plate 18 is a switchable quarter wave plate configured
to rotate the polarization of the light if the quarter wave plate
18 is activated and to not rotate the polarization of the light if
the quarter wave plate 18 is deactivated. In FIG. 1A, the quarter
wave plate 18 is depicted as a switchable wave plate to control the
transmission of light through the system 10 to the user's eye 26.
The switchable quarter wave plate may be activated or deactivated
by applying an electric current and may be constructed from
materials such as Pi-cell or polymer-stabilized liquid crystal
devices. FIG. 1A depicts the quarter wave plate 18 as controlled
via time-multiplexer 28. In the depicted embodiment,
time-multiplexer 28 is set to an "ON" state, which activates the
quarter wave plate 18 and allows light to pass through the system
as described above. In other embodiments, it should be appreciated
that other devices may be used to control the quarter wave plate
18.
Turning next to FIG. 1B, the time-multiplexer 28 is set to an "OFF"
state, which deactivates the quarter wave plate 18 and thus light
entering the system 10 with initial polarization P0 traveling along
the light path 12 will not be rotated to polarization P1 as it
passes through the quarter wave plate 18. Therefore, the light will
not obtain the correct polarization to reflect from the circular
polarizing reflector 20 and will instead be transmitted directly
though the circular polarizing reflector 20. If any light traveling
along light path 12 enters the user's eye 26, the user will see it
as emanating directly from image source 14. In certain embodiments
of this system, the light path 12 is configured to prevent such
light from being seen by the viewer. In other embodiments, the
system may be configured to transmit an unmagnified image of the
image source 14 to the user's eye 26.
Turning next to FIG. 1C, the time-multiplexer 28 may be configured
to activate and deactivate the quarter wave plate 18 at a set
frequency. Time-multiplexer 28 may be further configured activate
and deactivate the image source 14 at a complimentary frequency
such that the image source 14 only transmits light to the system 10
when the quarter wave plate 18 is activated. The system 10 may then
be configured to use the time-multiplexer as a filter preventing
unwanted glare, an unmagnified image from the image source 14 or
other noise from being transmitted through the system 10 to the
user's eye 26.
FIG. 1C depicts an embodiment of the system 10A, in which the image
source 14, the quarter wave plate 18, and the circular polarizing
reflector 20 tilted to an off-axis angle with respect to the
optical axis O in order to illustrate how the time-multiplexer 28
can be used to change the ratio of image light to ambient light
from the outside world. As described above, the image source 14
only transmits light to the system 10 when the quarter wave plate
18 is activated. Conversely, when the quarter wave plate 18 is not
activated, ambient light passes through initial polarizer 22 and is
then transmitted through curved polarizer 16, quarter wave plate
18, and reflective polarizer 20 with only nominal attenuation.
Thus, by varying the duty cycle of time-multiplexer 28, the amount
of ambient light can be adjusted from 0% to over 90% for one
polarization of ambient light, effectively acting as a global
dimming component for the outside world as seen by the user's eye
26. In some embodiments, the image source 14 is also modulated in
intensity, so that the display intensity can be dimmed
independently of the ambient image light.
Turning briefly back to FIG. 1A, the system 10 further includes an
initial polarizer 22 positioned upstream of the circular polarizing
reflector 20 on the light path, the initial polarizer 22 configured
to receive light from the image source 14 and transmit light with
an initial polarization P0 along the light path toward the curved
linear polarizing reflector 16. The curved linear polarizing
reflector 16 may be further configured to receive the light with
the initial polarization P0 from the initial polarizer 22 and
transmit the light along the light path toward the quarter wave
plate 18. The quarter wave plate 18 may be further configured to
rotate the polarization of the light received from the curved
linear polarizing reflector 16 from the initial polarization P0 to
the first polarization P1 and transmit the light along the light
path toward the circular polarizing reflector 20. In some
embodiments, the image source 14, the initial polarizer 22, the
curved linear polarizing reflector 16, the quarter wave plate 18,
and the circular polarizing reflector 20 may be configured in a
flat coaxial orientation. Thus, the system 10 may be configured
such that light transmitted from the image source 14 travels along
a substantially straight path through the initial polarizer 22, the
curved linear polarizing reflector 16 and the quarter wave plate
18. After passing through the quarter wave plate 18, the system 10
may be configured such that the polarization of the light is
rotated from the initial polarization P0 to the first polarization
P1. When the light of polarization P1 is incident on the circular
polarizing reflector 20, it will reflect back through the system 10
in the manner described above. In certain embodiments, the image
source 14 may be a transmissive or transparent display device,
allowing ambient light to enter the system through the initial
polarizer as well. In other embodiments, the image source 14 may be
configured as a transmissive display device overlaying a second
display device. In such embodiments, the system may be configured
to transmit light from both display devices to the user's eye 26.
In some examples, the differing distances between the display
devices and the curved polarizer 16 result in different display
planes being visible to the user at different depths.
Turning next to FIG. 2, a system 110 is depicted in which a fixed
wave plate 122 is positioned upstream of the circular polarizing
reflector 120 on the light path, the fixed wave plate 122
configured to receive the light from the image source 114 and
transmit the light with the first polarization P1 along the light
path in a direction of a prism 130 disposed between the fixed wave
plate 122 and the circular polarizing reflector 120. The prism 130
is configured to receive the light through a light input side 132
of the prism 130 and reflect the light off an internal surface 136
of the prism 130 via total internal reflection along the light path
toward the circular polarizing reflector 120. In FIG. 2, a second
prism 138 and a second matching prism 140 may be positioned between
image source 114 and the fixed wave plate 122. The second prism 138
may reflect light from a light source toward the image source 114,
while the second matching prism 140 may help to prevent light
reflected by the image source 114 from being refracted or reflected
away from the desired optical path 112. In certain embodiments
where image source 114 is an emissive display device the second
prism 138 and second matching prism 140 may be omitted. It should
also be noted that an air gap 142 may be created between the prism
130 and the quarter wave plate 118 so as to allow the light
entering the system to reflect off the internal surface 136 via
total internal reflection. In some embodiments, other means are
used to reflect the light from surface 136, including but not
limited to multilayer coatings.
The system 110 may be further configured such that an image source
114 is positioned at an angle 134 less than ninety degrees with
respect to an optical axis O of the curved linear polarizing
reflector 116 so as to project side-addressed light toward the
curved linear polarizing reflector 116. The prism 130 may be
positioned such that angle 134 between the optical axis O of the
curved linear polarizing reflector 116 and the axis A of the image
source 114 is less than 90 degrees. As a result, the overall size
of the system 110 can be decreased. The system 110 may be further
configured to receive ambient light through the curved linear
polarizing reflector 116. In certain embodiments, a
time-multiplexer 128 may be configured to control the image source
114 and quarter wave plate 118 in the manner described previously
and, in doing so, dynamically control the brightness of the
contrast between the ambient light and the light from the image
source 114.
Turning briefly back to FIG. 1A, the curved linear polarizing
reflector 16 may be a curved wire grid polarizing (WGP)
beamsplitter. A curved WGP beamsplitter may be manufactured so as
to reflect one polarization of light and transmit another with over
90 percent efficiency. In some embodiments, the curved linear
polarizing reflector 16 may be a curved WGP polarizing beamsplitter
that is configured to reflect one of S-polarized or P-polarized
light, and to transmit the other. In such embodiments, the system
10 may be configured to lose less than 10 percent of the total
light intensity when the light reflects off of curved linear
polarizing reflector 16. In addition, the circular polarizing
reflector 20 may be configured to be a cholesteric liquid crystal
(CLC) reflective polarizer. A CLC reflective polarizer may also be
manufactured to have a very high efficiency of reflection and
transmission of polarized light. Thus, in some embodiments, the
system 10 may be configured to use a CLC reflective polarizer as
circular polarizing reflector 20 so as to prevent a loss of light
intensity as light travels along light path 12 and bounces off of
circular polarizing reflector 20. In other embodiments, different
materials may be used for the curved linear polarizing reflector 16
and the circular polarizing reflector 20. For example, various
nanostructure devices exist or are currently under development that
may offer reflection and transmission efficiencies greater than or
equal to those of the curved WGP beamsplitter and CLC reflective
polarizer discussed above.
In FIG. 1A, the circular polarizing reflector 20 may be configured
to have a flat shape. In other embodiments, the circular polarizing
reflector 20 may be configured to have a curved shape. Likewise,
FIG. 1A depicts the curved linear polarizing reflector 16 as having
a curved shape. However, it should also be noted that in certain
embodiments, in which the circular polarizing reflector 20 has a
curved shape, the curved linear polarizing reflector 16 may also be
configured to have a flat shape.
Turning next to FIG. 3A, the system 10 may be configured as a
near-eye display device 302. The image source 14, curved linear
polarizing reflector 16, quarter wave plate 18, and circular
polarizing reflector 20 of FIG. 1A may be configured to be mounted
in the near-eye display device 302. FIG. 3A further depicts the
near eye display device 302 as incorporated into a housing 304 of a
head mounted display device 300. The head mounted display device
300 may be configured as a pair of glasses to be worn on the head
of the user. The near-eye display device 302 may be incorporated
into a portion of the housing 304 that would be positioned in front
of and close to a user's eye. In other embodiments, the near-eye
display device 302 may be incorporated into a hand-held or
wrist-worn device that is designed to be held near a user's eye
while in use. Such embodiments may take the form of a watch or a
screen on a hand-held device. In other embodiments, the display
device 300 may be configured as a stereoscopic head mounted display
device employing two near eye display devices 302, with one near
eye display devices 302 positioned in front of and close to each of
the user's eyes.
FIG. 3B shows the head-mounted display device 300 from a user's
perspective, looking through the near-eye display device 302
incorporated into the housing 304. The near-eye display device may
be configured to display mixed reality consisting of a real world
object 308, computer generated graphics 304 and computer generated
text 306. The near-eye display system may be further configured
such that the computer generated graphics 304 and computer
generated text 306 display information relating to the real world
object 308 so as to enhance the viewing experience of the user. For
example, FIG. 3B depicts real world object 308 as Mt. Everest,
computer generated graphics 304 as an indicator arrow pointing to
real world object 308, and computer generated text 306 as name
information for the real world object 308.
Turning next to FIG. 4, a flowchart is depicted showing a method
400 of transmitting light along a light path to a user's eye. The
method 400 includes, at step 402, reflecting light originating from
an image source having a first polarization off of a circular
polarizing reflector along the light path toward a quarter wave
plate. At 404, the method 400 further includes rotating the
polarization of the light from the first polarization to a second
polarization with the quarter wave plate and transmitting the light
with the second polarization along the light path toward a curved
linear polarizing reflector. At 406, the method 400 includes
reflecting the light off of the curved linear polarizing reflector
and transmitting the light along the light path back toward the
quarter wave plate. At 408, the method 400 includes rotating the
polarization of the light from a second polarization to a third
polarization with the quarter wave plate and transmitting the light
along the light path toward the circular polarizing reflector. At
410, the method 400 further includes transmitting the light through
the circular polarizing reflector along the light path toward the
user's eye. In addition, the method may further include optional
steps 414 and 418 at steps 404 and 408, respectively. Steps 414 and
418 include rotating the polarization of the light with the quarter
wave plate when the quarter wave plate is in an activated state and
not rotating the polarization of the light when the quarter wave
plate is in a deactivated state. Typically, this is accomplished in
the manner described above by the switchable quarter wave plate
being switched ON and OFF according to the signal of a time
multiplexer in the examples of FIGS. 1A-1C.
FIG. 5A and FIG. 5B depict two embodiments of the method 400,
respectively labeled as 400A, 400B, which respectively include
various substeps of step 402 in the method 400. As illustrated in
FIG. 5A, method 400A may include, at 502, converting the
polarization of the light originating from the image source to an
initial polarization via an initial polarizer positioned upstream
on the light path from the circular polarizing reflector. At 504,
the method 400A includes transmitting the light from the initial
polarizer along the light path toward the curved linear polarizing
reflector. At 506, the method 400A includes transmitting the light
through the curved linear polarizing reflector along the light path
toward the quarter wave plate. At 508, the method 400A includes
rotating the polarization of the light from the initial
polarization to a first polarization with the quarter wave plate.
At 510, the method 400A includes transmitting the light from the
quarter wave plate along the light path toward the circular
polarizing reflector. Following step 510, the method proceeds to
step 404 of method 400 illustrated in FIG. 4.
Turning next to FIG. 5B, the method 400B includes, at step 512,
converting the polarization of the light from the image source to a
first polarization via a fixed wave plate positioned upstream of
the circular polarizing reflector on the light path. At step 514,
the method 400B includes transmitting the light from the fixed wave
plate along the light path toward a prism positioned on the light
path between fixed wave plate and the circular polarizing
reflector. At step 516, the method 400B includes reflecting the
light via total internal reflection off of an interior surface of
the prism. At step 518, the method 400B includes transmitting the
light along the light path toward the circular polarizing
reflector. FIG. 5B depicts an additional optional step at 511, in
which the method 400B includes transmitting the light from the
image source at an angle less than ninety degrees with respect to
an optical axis of the curved polarizing reflector. Following step
518, the method proceeds to step 404 of method 400 illustrated in
FIG. 4.
It should be further noted that in certain embodiments of the
method 400, the curved linear polarizing reflector may be a curved
wire grid polarizing beamsplitter. Furthermore, the circular
polarizing reflector may be a cholesteric liquid crystal reflective
polarizer. In addition, the circular polarizing reflector may have
one of a flat or curved shape.
In some embodiments, the methods and processes described herein may
be tied to a computing system of one or more computing devices. In
particular, such methods and processes may be implemented as a
computer-application program or service, an application-programming
interface (API), a library, and/or other computer-program product,
e.g. to display an image via the disclosed display system
embodiments.
FIG. 6 schematically shows a non-limiting embodiment of a computing
system 600 that can enact one or more of the methods and processes
described above. Computing system 600 is shown in simplified form.
Computing system 600 may take the form of a head-mounted
see-through display device, as well as any other suitable computing
system, including but not limited to game consoles, one or more
personal computers, server computers, tablet computers,
home-entertainment computers, network computing devices, gaming
devices, mobile computing devices, mobile communication devices
(e.g., smart phone), and/or other computing devices.
Computing system 600 includes a logic machine 602 and a storage
machine 604. Computing system 600 may also include a display
subsystem 606, input subsystem 608, communication subsystem 610,
and/or other components not shown in FIG. 6.
Logic machine 602 includes one or more physical devices configured
to execute instructions. For example, the logic machine may be
configured to execute instructions that are part of one or more
applications, services, programs, routines, libraries, objects,
components, data structures, or other logical constructs. Such
instructions may be implemented to perform a task, implement a data
type, transform the state of one or more components, achieve a
technical effect, or otherwise arrive at a desired result.
The logic machine may include one or more processors configured to
execute software instructions. Additionally or alternatively, the
logic machine may include one or more hardware or firmware logic
machines configured to execute hardware or firmware instructions.
Processors of the logic machine may be single-core or multi-core,
and the instructions executed thereon may be configured for
sequential, parallel, and/or distributed processing. Individual
components of the logic machine optionally may be distributed among
two or more separate devices, which may be remotely located and/or
configured for coordinated processing. Aspects of the logic machine
may be virtualized and executed by remotely accessible, networked
computing devices configured in a cloud-computing
configuration.
Storage machine 604 includes one or more physical devices
configured to hold instructions executable by the logic machine to
implement the methods and processes described herein. When such
methods and processes are implemented, the state of storage machine
604 may be transformed--e.g., to hold different data.
Storage machine 604 may include removable and/or built-in devices.
Storage machine 604 may include optical memory (e.g., CD, DVD,
HD-DVD, Blu-Ray Disc, etc.), semiconductor memory (e.g., RAM,
EPROM, EEPROM, etc.), and/or magnetic memory (e.g., hard-disk
drive, floppy-disk drive, tape drive, MRAM, etc.), among others.
Storage machine 604 may include volatile, nonvolatile, dynamic,
static, read/write, read-only, random-access, sequential-access,
location-addressable, file-addressable, and/or content-addressable
devices.
It will be appreciated that storage machine 604 includes one or
more physical devices. However, aspects of the instructions
described herein alternatively may be propagated by a communication
medium (e.g., an electromagnetic signal, an optical signal, etc.)
that is not held by a physical device for a finite duration.
Aspects of logic machine 602 and storage machine 604 may be
integrated together into one or more hardware-logic components.
Such hardware-logic components may include field-programmable gate
arrays (FPGAs), program- and application-specific integrated
circuits (PASIC/ASICs), program- and application-specific standard
products (PSSP/ASSPs), system-on-a-chip (SOC), and complex
programmable logic devices (CPLDs), for example.
The terms "module," "program," and "engine" may be used to describe
an aspect of computing system 600 implemented to perform a
particular function. In some cases, a module, program, or engine
may be instantiated via logic machine 602 executing instructions
held by storage machine 604. It will be understood that different
modules, programs, and/or engines may be instantiated from the same
application, service, code block, object, library, routine, API,
function, etc. Likewise, the same module, program, and/or engine
may be instantiated by different applications, services, code
blocks, objects, routines, APIs, functions, etc. The terms
"module," "program," and "engine" may encompass individual or
groups of executable files, data files, libraries, drivers,
scripts, database records, etc.
When included, display subsystem 606 may be used to present a
visual representation of data held by storage machine 604. This
visual representation may take the form of a graphical user
interface (GUI). As the herein described methods and processes
change the data held by the storage machine, and thus transform the
state of the storage machine, the state of display subsystem 606
may likewise be transformed to visually represent changes in the
underlying data. Display subsystem 606 may include one or more
display devices utilizing virtually any type of technology. Such
display devices may be combined with logic machine 602 and/or
storage machine 604 in a shared enclosure, or such display devices
may be peripheral display devices.
When included, input subsystem 608 may comprise or interface with
one or more user-input devices such as a keyboard, mouse, touch
screen, or game controller. In some embodiments, the input
subsystem may comprise or interface with selected natural user
input (NUI) componentry. Such componentry may be integrated or
peripheral, and the transduction and/or processing of input actions
may be handled on- or off-board. Example NUI componentry may
include a microphone for speech and/or voice recognition; an
infrared, color, stereoscopic, and/or depth camera for machine
vision and/or gesture recognition; a head tracker, eye tracker,
accelerometer, and/or gyroscope for motion detection and/or intent
recognition; as well as electric-field sensing componentry for
assessing brain activity.
When included, communication subsystem 610 may be configured to
communicatively couple computing system 600 with one or more other
computing devices. Communication subsystem 610 may include wired
and/or wireless communication devices compatible with one or more
different communication protocols. As non-limiting examples, the
communication subsystem may be configured for communication via a
wireless telephone network, or a wired or wireless local- or
wide-area network. In some embodiments, the communication subsystem
may allow computing system 600 to send and/or receive messages to
and/or from other devices via a network such as the Internet.
It will be understood that the configurations and/or approaches
described herein are exemplary in nature, and that these specific
embodiments or examples are not to be considered in a limiting
sense, because numerous variations are possible. The specific
routines or methods described herein may represent one or more of
any number of processing strategies. As such, various acts
illustrated and/or described may be performed in the sequence
illustrated and/or described, in other sequences, in parallel, or
omitted. Likewise, the order of the above-described processes may
be changed.
The subject matter of the present disclosure includes all novel and
nonobvious combinations and subcombinations of the various
processes, systems and configurations, and other features,
functions, acts, and/or properties disclosed herein, as well as any
and all equivalents thereof.
* * * * *
References